NTSB Safety Recommendation P-83-022

NTSB safety recommendation P-83-022.

THE NTSB RECOMMENDS THAT THE MISSISSIPPI RIVER TRANSMISSION CORPORATION: REQUIRE CONTINUOUS MONITORING FOR THE PRESENCE OF GAS WHEN WORK IS TO BE PERFORMED IN THE VICINITY OF PIPELINE SECTIONS THAT HAVE BEEN ISOLATED FROM GAS UNDER HIGH PRESSURE SOLELY BY CLOSED VALVES AND BY THE INSTALLATION OF TEMPORARY END CAPS.

Priority: CLASS II

Overall Status: Closed - Acceptable Alternate Action

Issued Date: 1983-09-07

Adopted Date: 1983-07-26

Overall Date Closed: 1989-04-27

Synopsis: ON OCTOBER 1, 1982, A 1/4-INCH-THICK STEEL PLATE, WHICH HAD BEEN WELDED BY A WORK CREW TO CAP TEMPORARILY THE OPEN END OF A SECTION OF A 22-INCH-DIAMETER GAS TRANSMISSION PIPELINE WHICH HAD BEEN ISOLATED BY CLOSING A GATE VALVE AND THEN GAS FREED, BLEW OFF UNDER AN INITIAL PRESSURE OF POSSIBLY 260 PSIG. RAPIDLY ESCAPING NATURAL GAS FROM THE PIPELINE, WHICH HAD ACCUMULATED DUE TO A LEAK IN THE GATE VALVE, IGNITED ALMOST IMMEDIATELY AND THE ENTIRE WORK AREA AND A PORTION OF U.S. ROUTE 65 WERE MOMENTARILY ENGULFED IN FLAMES. SEVEN PERSONS WHO WERE WORKING TO REPLACE A SECTION OF THE PIPELINE UNDER THE ROAD ABOUT 2 MILES SOUTH OF PINE BLUFF, ARKANSAS, WERE BURNED AND HOSPITALIZED. RESULTANT PROPERTY DAMAGE WAS MINIMAL.

Ntsbnumber: FTW83LA007

Report Number: PAR-83-03

Addressee Name: Mississippi River Transmission Corporation

Addressee Status: Closed - Acceptable Alternate Action

Addressee Date Closed: 1989-04-27

Addressee Acronym: MRT

Addressee Organization Type: P-Private Industry

Communication Date: 1988-07-18

Communication Type: Official Correspondence

Communication Contents: ANYTIME THE ABOVE SITUATION EXISTS A CHART RECORDER IS TO BE INSTALLED TO CONTINUOUSLY MONITOR PRESSURE.

Addressee Acronym: MRT

Addressee Organization Type: P-Private Industry

Communication Date: 1988-11-16

Communication Type: Official Correspondence

Communication Contents: SAFETY RECOMMENDATION P-83-22 SUGGESTS THAT MRT REQUIRE CONTINUOUS MONITORING FOR THE PRESENCE OF GAS WHERE WORK IS TO BE PERFORMED IN THE VICINITY OF PIPELINE SECTIONS THAT HAVE BEEN ISOLATED FROM GAS UNDER HIGH PRESSURE SOLELY BY CLOSED VALVES AND BY THE INSTALLATION OF TEMPORARY END CAPS. IN AN EFFORT TO SATISFY THIS RECOMMENDATION, MRT EMPLOYS SEVERAL PRECAUTIONS BEFORE BEGINNING WORK AND DURING THE TIME WORK IS BEING PERFORMED ON THE PIPELINE. INCIDENTALLY, THE VAST MAJORITY OF WORK IS PERFORMED IN OPEN AREAS DUE TOT COMPRESSOR BUILDINGS ARE EQUIPPED WITH ALARMS TO WARN OF THE PRESENCE OF GAS. PRIOR TO BEGINNING EACH JOB, MRT TAKES A NUMBER OF PRECAUTIONS, SUCH AS A WELD CAP WITH A FULL PRESSURE WELD TO SEAL OFF THE PIPE, LAMB AIR MOVERS TO SUCTION ANY GAS AWAY FROM THE SITE, AND VENTING OF THE PIPELINE TO PREVENT PRESSURE BUILD UP. MRT CAREFULLY TESTS THE ATMOSPHERE AROUND EACH WORK AREA FOR THE PRESENCE OF GAS PRIOR TO BEGINNING WORK. IN UNUSUAL SITUATIONS WHEN WORK MUST BE PERFORMED IN THE PRESENCE OF GAS, SPECIAL PRECAUTIONS ARE TAKEN. FOR INSTANCE, WHEN WORK MUST BE DONE WITHOUT A FULL PRESSURE WELD TO SEAL OFF THE PIPE, MRT HAS ESTABLISHED A POLICY OF EMPLOYING A PRESSURE RECORDER TO CONTINUOUSLY RECORD GAS PRESSURE IN THE ISOLATED SECTION OF PIPE. IF GAS IS PRESENT IN THE ISOLATED SECTION OF PIPE, THE PRESSURE RECORDER WILL REFLECT THAT FACT. WE BELIEVE THAT THE PRESSURE RECORDER PROVIDES SUFFICIENT ASSURANCE THAT GAS WILL NOT THEREAFTER LEAK UNDETECTED INTO THE ISOLATED SECTION OF PIPE. SINCE MOST WORK IS PERFORMED OUTDOORS, AND BECAUSE WE USE A VARIETY OF PRECAUTIONS, WE BELIEVE THAT ADDITIONAL CONTINUOUS MONITORING FOR THE PRESENCE OF GAS AT WORK AREAS IS UNNECESSARY. WE BELIEVE THAT FURTHER MEASURES TO MONITOR FOR THE PRESENCE OF GAS WILL NOT ADD TO THE SAFETY OF THESE SITES AND, IN FACT, WOULD NOT HAVE PREVENTED THE PINE BLUFF ACCIDENT IN 1982. THAT ACCIDENT, OF COURSE, WAS CAUSED BY THE SUDDEN RELEASE OF GAS DUE TO THE IMPROPER CLOSING OF THE VENT VALVES. MONITORING THE WORK SITE FOR THE PRESENCE OF GAS WOULD HAVE BEEN USELESS.

Addressee Acronym: MRT

Addressee Organization Type: P-Private Industry

Communication Date: 1988-06-08

Communication Type: Official Correspondence

Addressee Acronym: MRT

Addressee Organization Type: P-Private Industry

Communication Date: 1989-04-27

Communication Type: Official Correspondence

Addressee Acronym: MRT

Addressee Organization Type: P-Private Industry

Communication Date: 1988-09-22

Communication Type: Official Correspondence